Download Science 8 - Lesson 14 Guided Notes, Part One, Answer Key

DO NOW
In a minimum of 5 lines, explain the difference between a rock and a wooden
plank. Include such things as physical make up and how it was made.
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UNIT TWO:
ECOLOGY AND EVOLUTION
Ecological Relationships and Systems
PART ONE: Parts of an Ecosystem
Vocabulary Review
Write down the following terms in your notebook, and write the definitions of each:
Ecosystem
Mutualism
Abiotic factors
Commensalism
Biotic factors
Parasitism
Competition
Parasite
Predator
Host
Prey
Biome
Symbiosis
Wetland
Introduction
Such news often flashes across television screens, newspapers, and the Internet.
-We are fascinated and frightened by these natural events, but there are other stories, as
well.
-Some tell of projects to restore wetlands in southern Florida and along the Mississippi
River for the purpose of controlling floods and droughts.
-Others report on improvements in air and water quality as a result of changes in the
gasoline that we put in our cars.
-Like all organisms, we interact with our environment.
-To understand these interactions better and to learn how to control them, we turn to the
science called ecology.
Interactions and Interdependence
Ecology is the scientific study of interactions among organisms and between organisms and
their environment, or surroundings.
-The word ecology was coined in 1866 by the German biologist Ernst Haeckel.
-Haeckel based this term on the Greek word oikos, meaning house, which is also the root of
the word economy.
-Haeckel saw the living world as a household with an economy in which each organism
plays a role.
Nature’s “houses” come in many sizes- from single cells to the entire planet.
-The largest of these houses is called the biosphere.
-The biosphere contains the combined portions of the planet in which all of life exists,
including land, water, and air, or atmosphere.
-It extends from about 8 kilometers above Earth’s surface to as far as 11 kilometers below
the surface of the ocean.
-Interactions within the biosphere produce a web of interdependence between organisms
and the environment in which they live.
-Whether it occurs:
-On top of a glacier
-In a forest
-Deep within an ocean trench
-The interdependence of life on Earth contributes to an ever-changing, or dynamic,
biosphere.
Levels of Organization
To understand relationships within the biosphere, ecologists ask questions about events and
organisms that range in complexity from a single individual to the entire biosphere.
-The many levels of organization that ecologists study are as follows:
Some ecologists study interactions between a particular kind of organism and its
surroundings.
-Such studies focus on the species level.
-A species is a group of organisms so similar to one another that they can breed and
produce fertile offspring.
-Other ecologists study populations, or groups of individuals that belong to the same
species and live in the same area.
-Still other ecologists study communities, or assemblages of different populations that live
together in a defined area.
Ecologists may study a particular ecosystem.
-An ecosystem is a collection of all the organisms that live in a particular place,
together with their nonliving, or physical, environment.
-Larger systems called biomes are also studied by teams of ecologists.
-A biome is a group of ecosystems that have the same climate and similar dominant
communities.
-The highest level of organization that ecologists study is the entire biosphere itself.
Ecosystems in Detail
Ecosystems are influenced by a combination of biological and physical factors.
What are the biological influences on organisms within an ecosystem called?
-Biotic factors.
-Examples?
-The entire living cast of characters with which an organism might interact.
-Birds, trees, mushrooms, bacteria.
-AKA the ecological community.
Example:
-Biotic factors that influence a bullfrog might include:
-The tiny plants and algae it eats as a tadpole.
-The herons that eat the adult frog.
-Other species that compete with the bullfrog for food or space.
What are the physical (nonliving) factors called that shape ecosystems?
– Abiotic factors.
– Example: The climate of an area includes abiotic factors such as:
Temperature, precipitation, humidity, wind, nutrient availability, soil type and
sunlight
Together, biotic and abiotic factors determine the survival and growth of an organism and
the productivity of the ecosystem in which the organism lives.
Ecological Methods
Ecologists use a wide range of tools and techniques to study the living world.
-Some use binoculars and field guides to assess changes in plant and wildlife communities.
-Others use studies of DNA to identify bacteria in the mud of coastal marshes.
-Still others use radio tags to track migrating wildlife or use data gathered by satellites.
Regardless of the tools they use, scientists conduct modern ecological research using three
basic approaches:
-Observing
-Experimenting
-Modeling
-All of these approaches rely on the application of scientific methods to guide ecological
inquiry.
Ecological Methods - Observing
Observing is often the first step in asking ecological questions.
-Some observations are simple:
-What species live here?
-How many individuals of each species are
there?
-Other observations are more complex and may form the first step in designing experiments
and models.
Ecological Methods - Experimenting
Experiments can be used to test hypotheses.
-An ecologist may set up an artificial environment in a laboratory to imitate and
manipulate conditions that organisms would encounter in the natural world.
-Other experiments are conducted within natural ecosystems.
Ecological Methods - Modeling
Many ecological phenomena occur over long periods of time or on such large spatial scales
that they are difficult to study.
-Ecologists make models to gain insight into complex phenomena such as the effects of
global warming on ecosystems.
-Many ecological models consist of mathematical formulas based on data collected
through observation and experimentation.
-The predictions made by ecological models are often tested by further observations and
experiments.